Compounded lubricating oil



Patented Feb.- 12, 1946 UNITED.- STATES PATENT 7 OFFICE COMPOUNDEDLUBRICATIN G OIL George H. Denison, Jr., and Paul C. Condit,

Berkeley, Calif., assignors, by mesne assignments, to CaliforniaResearch Corporation, San Francisco, Calif., a corporation oi! DelawareNo Drawing. Application October 18, 1943, Serial No. 506,726

8 Claims.

our copending application Serial No. 432,040 (filed February 23, l942),now United States Patent No. 2,346,155, issued April 11, 1944.

The hydrocarbon oils compounded according to the invention are oils oflubricating viscosity and will usually be petroleum distillates orresidua of suitable viscosity; e. g. parafiinic, naphthenic and mixedbase lubricating oils including highly refined and moderately refinedoils. However, synthetic oils such as oily olefin polymers, amylnaphthalene, etc., may be used.

The organic sulfides used may be represented by the formula Rl- (S n-R2wherein R1 and R2 are aliphatic groups and n is 1, 2 or 3. The groups R1and R2 may be like or unlike; preferably they are both alkyl groups ofat least eight carbon atoms apiece, but they may be shorter groups andthey may be cycloalkyl or aralkyl groups. Examples of such sulfurcompounds are: dibutyl, diamyl, butyl ethyl, dihexyl, dicyclonexyl,dioctyl, dilauryl, dicetyl and diparafin sulfides, disulfides andpolysulfides. A means of preparing these sulfur compounds comprisesreacting a chlorinated hydrocarbon such as cetyl chloride or a mixtureof chlorinated hydrocarbons such as chlorinated paraflin Wax with sodiumsulfide or sodium polysulfide in aqueous or alcoholic solution toreplace all or part of the chlorine with sulfur. Examples of thepreparation of aliphatic sulfides and polysulfides' will be found in thegeneral literature and examples of the preparation of sulfides fromchlorinated paraihn wax will be found in Turner, '0. S. Patents2,124,598 and 2,192,700. a

The dithiocarbamate used according to the invention is the salt of anacid having the formula:

at least slightly soluble in oil. The ES may be like or unlike and theymay be alkyl, cycloalkyl, aryl, alkaryl or aralkyl groups. The readiestmethod of preparation comprises reacting a secondary amine with carbondisulfide in aqueous or alcoholic caustic soda or caustic. potash.General preparative methods are available ,in the literature.Preferably, there are used in accord-- ance with the inventiondithiocarbamates made by extracting cyclic petroleum nitrogen bases fromcracked naphtha from California crudes and reducing the same (seeRutherford, U. S. Patent 2,302,655) and then reacting the reducedpetroleum nitrogen bases with carbon disulfide in aqueous caustic alkalisolution. The alkali metal dithiocarbamate thus obtained may berecovered from aqueous solution by crystallization, but as thepolyvalent metal dithiocarbamates are preferred it will be the usualpractice to add to the aqueous reaction mixture an aqueous solution of asalt of a polyvalent metal, e. g. calcium chloride or zinc sulfate, andprecipitate the desired polyvalent metal dithiocarbamate. This may bepurifled by crystallization from alcoho1 solution.

Dithiocarbamates so prepared are herein called petroleum basedithiocarbamates. Examples of these and other dithiocarbamates which maybe used in hydrocarbon oils in conjunction with the above mentionedsulfur compounds are sodium, potassium, calcium, zinc, cadmium andaluminum petroleum base dithiocarbamates; the same metal salts ofdibutyl dithiocarbamic acid and the same metal salts of diphenyl anddicetylphenyl dithiocarbamlc acids.

The proportion of organic sulfide in the finished oil may be as littleas 0.05% but about 0.1% to 2% is preferred. The dithiocarbamates maylikewise be present in amount as low as 0.05% but about 0.1% to 2% ispreferred. In each case, percentages are by weight based on the finishedoil. Concentrates containing from 5 to 50 percent each of organicsulfide and dithiocarbamate in mineral lubricating oil may also beprepared for later blending with more oil to produce a finished,compounded oil.

' Among the advantages of the'hydrocarbon oilorganicsulfide-dithiocarbamate composition of the present invention areincreased resistance to deterioration of the oil caused by heat andoxidation; reduced corrosiveness of the oil to cadmium-silver and/orcopper-lead types of alloy bearings; reduced sludging of the oil andreduced tendency of the oil to foul piston walls, piston rings andpiston ring slots; and reduced tendency oi the 1011 to cause or permitpiston ring sticmng.

The following test data show the cooperative relationship between thesulfide type of additive and the dithiooarbamate additive of the inven-'tion. The data are from an oxidation test particularly described inIndustrial and Engineering Chemistry, vol. 28, page 26, 1936. The testswere carried out at 340 F. and the amount of oxygen absorptionper 100cc. of oil was measured at a various time intervals.

Cc. oxygen absorbed/100 cc.oil in- .Whlle salts, more particularlypolyvalent metal salts, of organo substituted dithiocarbamic acids arepreferred, salts of organo substituted car-- bamic acids in general maybe used in accordance with the invention.

asse ses I' I wherein R1 and R2 are aliphatic groups and n is a g wholenumber irom 1 to 3, inclusive, and asmall As stated, polyvalent metal"petrole V base-'- dithiocarbamatesare preferred as one of thcompounding agents of the present invention. From the properties andreactions of these petroleum base dithiocarbamates as wellas those ofthe cracked petroleumnitrogen bases from which they arederived, it isdeduced that the "petroleum base dithiocarbamates are predominantly .oneor more, probably a mixture 01' substances having the followingstructural formulae:

I n a In theabove formulae, R1; R2 and R: represent v alkyl groups,which may be attached at the points shown or at other points on thepiperidine ring, and'Ri and the sum R2+Ra each contains an average of 5carbon atoms.

As used in the appended claims the term petroleum base" dithiocarbamatemeans a dithio- -car bamate wherein the nitrogen forms part of a ringsuch as a piperidine ring. which ring contains one or more alkyl groupson the carbon part of the ring.

We claim :v

a 1. A composition comprising a major propor-- vtion ot a hydrocarbonoil, a small amount. sumcient to stabilize the oil against oxldatiomot acompound having the fdrmula amount not'less than about 0.05% by weightbased on the finished composition or a salt 0! a thiocarbamfc acidcontaining an organic substituent. A

2. A composition comp a major proportion of a hydrocarbon oi a thioetherpresent in a small amount, sufficient to stabilize said oil againstdeterioration under oxidizing conditions and aim ll amount not less thanabout 0.05% by weight based on the finished composition of a salt of a'thiocarbamic acid containing an organic substituent.

3. A composition comprising a major proportion of a hydrocarbon oil, athioether present in a small amount sufllcient to stabilize said oilagainst deterioration under oxidizing conditions. and a small amount notless than about 0.05% by weight based on the finished composition 01 apolyvalent metal salt of athiocarbamic acid containing an organicsubstituent.

4. A lubricating oil comprising: a major proportion of a mineral oil oflubricating viscosity; about 0.1 to 2 percent by weight on the finishedoil of an oil-soluble compound or mixture of oilsoluble compounds havingthe structure c 5 c I I a wherein n is 1, 2 or 3 and the carboma'tomsshown are aliphatic carbon atoms; and about 0.1 to 2 percent by weighton the finished oil of a polyvalent metal salt of a dithiocarbamic acidor mixture of, dithiocarbamic acids having the formula N-i-s-ri niwherein R1 and R: are oil-solubilizing groups of hydrocarbon structure.

5. Alubricating oil comprising a mineral oil of lubricating viscosity,about 0.1 to 2 percent .by weight on the finished voil'ot an oil-solubledialkyl thioether and about 0.1.to 2 percent by weight on the finishedoilot polyvalent metal "petroleum base" dithiocarbamate. 6. The oil ofclaim 5, wherein metal is zinc. a

7. A lubricating oil comprising a mineral oil of lubricating viscosity,about 0.1 to 2 percent by weight on the finished oil oi the condensationproductof chlorinated paraflin wax and an alkali metal sulfide and about0.1 to 2 percent byweight on the finished oil of polyvalent metal"petroleum 'GEOBGEYH. name on, JR. ram. c. oounrr.

said polyvalent

